Transformer



ma ma? A. A. KENT TRANSFORMER July 2, 1929,

Original Filed Feb. 6, 1924 M INWR.

1 1 ATTORNEY.

Patented July 2, 1929.

PATENT OFFICE.

ABTHUR ATWATER KENT, OF ARDMOBE, PENNSYLVANIA.

TRANSFORMER.

Application filed February 6,1924, Serial No. 691,071. Renewed October 13,1928.

My invention relates to transformers, such, for example, as are utilizable in radio systems, and more particularly my invention re- I lates to radio or high frequency transformers.

In accordance with my invention, the transformer windings are disposed, respectively, inside and outside of a hollow support, the inside winding comprising a selfsupporting .or formed coil which is introduced into the interiorof the support and and additionally loosening the coupling be-' tween the transformer windings.

My invention resides in a transformer-or coil structure of the character hereinafter described and claimed.

For an illustration of one of the various forms my invention may take, reference is to be had to the accompanying drawing, in which:

Fig. 1 is a vertical sectional view, partly in elevation, of structure embodying my invention.

Fig. 2 is a perspective view of a selfsustaining coil or winding.

Figs. 3 and 4 are, respectively, top and bottom plan views of the structure illustrated in Fig. 1.

Fig. 5 is a diagrammatic view illustrating one of the relations in which my structure is utilizable;

Referring to the drawing, 1 is a support, preferably of insulating material, such as molded bakelite, condensite or the like, in the form of a tube or shell having, if desired, the end closure or wall 2 and provided at its base with a flange 3 provided with holes 4: to receive screws or equiyalent means for securing the structure to a support or base.

'[Within'the shell or hollow support is provided the ledge 52', against or adjacent which is disposed the coil 6, constituting one winding of the transformer Whose other winding 7 is disposed on the exterior of the shell or support 1n engagement with or adjacent to .the external ledge 8.

The coil 6 comprises any suitable number oflayers of insulated conductor, as enamel, silica or cotton-covered copper Wire. In the example illustrated, there is but one layer of conductor constituting a formed or self-supporting winding, the I neighboring turns or convolutions being .held to each other by any suitable binding material, as

is hexagonal; though it will be understood.

that it may have any other suitable or desirable number of sides, for it may be triangular, square, pentagonal, octagonal, etc. The winding is prcferably a regular or equilateral polygon, though when suitable or desirable the length of its sides may be unequal. Theexternal diameter or size of the coil is preferably such that at its corners or vertices 10, preferably slightly rounded, itis substantially or approximate 1y equalto the internal diameter of the shell or support 1. at least adjacent the region where the coil is to be held or fixed. The coil 6 at its vertices 10 engages the led e 5, and is there held or secured,.as by a p ication of any suitable binding material 11, such as collodion or equivalent.

The polygonal form of the coil 6 is of advantage in'that it is more readily introduced into and held in the support or tube 1 than a circular coil or coil of the same shape as the cross section of the chamber within the tube or support-l. There is a further advantage, particularly in a radio or high frequency transformer, that the coupling between or mutual inductance of the two windings is iooser or less, since the area enclosed by the winding 6 when of polygonal form is less than when circular in form, and

accordingly the number of .lines of force common to or threading both coils is less-- ing outwardly through a hole 13 and backwardly throu h the adjacent hole 13 to form on the outside of the structure a loop 14, the reentrant portions of the ends 12 then extending downwardly through'the base or support to which the flange 3 is secured for connecting the winding 6 in circuit..

The exterior winding 7 may be separately formed and placed upon the support '1, or may be wound in place upon the support, which is slightly tapered, longitudinally, more particularly for permitting easy withdrawal of the support fromjthe mold in which formed. The ends 15 of the winding 7 extend through holes to the interior of the shell and thence downwardly through the base or support to which the flange 3 is attached for connecting the'winding 7 in circuit.

While the winding 7 is shown as applied upon the exterior of the support 1, it may also be applied upon the interior of the suport l,'and in such case may be polygonal in form. It may also be polygonal in form when applied upon the exterior of the support 1, in which'case the winding will at its sides intermediate its vertices engage or closely approach the cylindrical or conical support 1; Or the winding 6 may be placed upon the exterior of the support 1 with the winding 7 either on the exterior or interior of the support, either or both" coils again.

being olygonal in form.

In t e example illustrated, the winding 6 is placed adjacent one end of the winding 7 thereby further loosening the coupling, particularly when the length of the coil 6 is materially less than that of the coil 7, -as is the case in the example illustrated, since a relatively large ratio of transformation, as of the order offour, is utilized.

In Fig. 5 there is illustrated one of the circuitzarrangements in which a transformer of'the character described is utilizable. It

is there employed to couple the anode orplate circuit of the radio frequency amplifying audion or tube V with the grid or in- 'In the example illustrated, the winding 6 is the primary and winding 7 the secondary of the radio frequency transformer.

For certain purposes, it is desirable that the coupling between the transformer windings 6 and/ 7 shall be loose, as indicated in Fig. 5, and this looseness V of coupling is effected not only by the radial distance apart of the windingsfi and 7, but also by the location of the relatively short winding adjacent one end of the other winding, as ,7, and is further increased by the polygonal form of one or both windings.

While the ledge structure 5 may be utilized as described, it shall be understood that it may be omitted, and the coil 6.sccnred in position without recourse to the ledge 5 or equivalent, as by cementing or otherwise attaching the verticeslO of the coil 6 to a suitablesupport, which in some instances may be a self-supporting coil 7, without recourse to a support 1.

It shall be further understood that the position of the coil 6 with respect to the coil cular and the other polygonal, the mean or average distance between the windings of the two coils isincrea'sed, thereby effecting greater looseness of coupling; and when the polygonal coil is disposed within an outer circular coil, notwithstanding close approach of the vertices of the polygonal coil to the outer coil, the mean distance between the coils is greater than the distance between the vertices and the outer coil, thereby eifecting loose coupling.

What I claimis:

1. A transformer comprising primary and secondary windings and a support therefor, at least one of said windings being a polygonal coil engaging said support at a plurality of 'circumferentiall spaced vertices between which said coil is spaced from said support. a

2. A transformer comprising primary and secondary windings anda support therefor, at least one of said windings being a poly onal coil, and means securing said coil to said support at a plurality of circumferentially spaced vertices between which said coil is spaced from said support.

' 3. A transformer comprising primary and secondary windings and a' hollow support therefor, at least one of said windings being a polygonal coil disposed withinsaid support and in contact with said support between which said coil is spaced at its vertices from said support.

A transformer comprising primary and secondary windings and a support therefor,

at least one of said windings being a polygonal coil comprising a plurality of turns disposed side by side longitudinally of the axis of the coil, said coil in contact withsaid support at a plurality of circumferentially spaced vertices. p

5. A transformer comprising primary and llt secondary windings and a support therefor, at least one of said windings being a polygonal coil comprising a plurality of turns disposed'side by side longitudinally of the axis of the coil,'sai'd coil approaching and attached to said support'only at a plurality of circumferentiallyspaced vertices.

6. Atransformer comprising primary and secondary windings an'd a support therefor, at least one of said windings being a selfsustaining polygonal coil engaging said support at. a plurality of circumferentially spaced vertices between which said coil is spaced from said support.

7. A transformer comprising primary and secondary windings-and a support therefor, at least one of said windings being a selfsustaining polygonal coil attached to said support at a plurality of circumferentially spaced vertices between which said coil is spaced from said support.

8. A transformer comprising primary and secondary windings and a support therefor, at least one of said windings being a selfsustaining polygonal coil comprising a plurality of turns disposed side by side longi tudinally of the axis of the coil, said coil in contact with said support at a plurality of 'circumferentially spaced vertices between which said.coil is spaced from said support.

9.' A transformer comprising primary and secondary windings and ahollow support therefor, ledge structure on the-interior of said support, and a polygonal coil disposed within said support with its vertices disposed upon said ledge structure.

10. A radio frequency transformer comprising primary and secondary windings and a hollow support therefor, one of saidwindings disposed on the exterior of said support, another of said windings being polygonal in form and havinga plurality of turns disposed side by side longitudinally of its axis, said polygonal winding disposed within said support with its vertices only adjacent the inner wall of said support, and means for holding said polygonal winding in position within said support.

11. A radio frequency transformer comprising windings for effecting coupling between output and input circuits of-thermionic vacuum tubes comprising a hollow support,-one of said windings disposed upon the exterior of said support, another of said windings being polygonal in form and comprising a plurality of turns disposed sideby side axially of the winding, said polygonal winding disposed within said support with its vertices approaching the inner wall of said support, and means for holding said polygonal winding in position with respect to said support.

12. A transformer comprising primary and secondary windings and a cylindrical support thereof, at least oneof said windings being a polygonal coil and in contact with said support at a plurality of circumferentially spaced points between which said coil is spaced from said support.

13. A transformer comprising a cupshaped member of insulating material, and primary and secondary windings disposed respectively on the interior and exterior of said member.

14. A transformer comprising a hollow supporting member having structure projecting inwardly from the interior wall thereof, a transformer winding disposed on the exterior of said member, and a second winding disposed interior-1y thereof in position determined by said projectingstructure.

In testimony whereof I have hereunto aflixed my signature this 4:" day of February, 1924;.

ARTHUR ATWATER KENT.

CERTIFICATE OF CORREQTEQN.

Patent No. 1, 719,057.

Granted July 2, 192%, to

ARTHUR ATWATER KENT.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Page 2, line 119, claim 3, after the word "support" insert-the words "at its vertices"; same page and claim, lines 120 and 121i, strike out the words 'iat its vertices"; and that the. said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent @tiice.

Signed and sealed this 24th day of Jane, A. D. 11930.

(Seal) M. J. Moore, Acting Commissioner of Patents.

CERTIFICATE (i CORREGTIQN.

Patent No. 1,719,057. Granted July 2, 1929, to

ARTHUR ATWATER KENT. D

It is hereby certified that error appears in the printed specification oi the above numbered patent requiring correction as follows: Page 2, line 119, claim 3, after the word "support" insert the words "at its vertiees"; same page and claim, lines 120 and 121, strike out the words "at its vertices"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 24th day of Jane, A. D. 1931).

M. J. Moore, (Seal) Acting Commissioner of Patents. 

